> So because there is dependence on some monopolistic entity for contract disputes (there really shouldn't be)
Its definitional: if you aren't seeking the threat of state enforcement to enforce a set of mutual promises, you don't have a contract, you have a mutual set of promises that lacks the intent necessary to form a contract.
> then that gives justification for that entity to intrude on voluntary actions?
Yes, using the threat of action by other people to get what you want gives those other people a right to a voice in what you can use that threat to support.
> Seems like a logical fallacy to me.
Subjective appearance can say as much about the one seeing as the thing being seen.
> How about we let people transact peacefully and deal with the problems on a case-by-case basis instead of lumping everyone under the same law that allows no room for exploration.
Enforcement of existing laws, civil and criminal, is done on a case-by-case basis by actual people; even if something creates a civil or criminal cause of action, the party (the prosecutorial authority of the state, in criminal cases) with the cause of action may choose not exercise it, and jury nullification is thing, so, largely, what you call for is the status quo.
If you think the specific parameters of the existing law are drawn incorrectly, you probably ought to address your specific problem rather than calling for abstract features that already exist in the current system.